Ventilation device

ABSTRACT

This invention relates to a ventilation device which may be used in an aircraft window and which has an outer rigid portion peripherally surrounding at least a portion of an inner flexible portion and physically connected thereto. The inner flexible portion has at least one portion thereof having a lineal physical dimension greater than the distance between first points on the outer rigid portion where the flexible portion physically connects at the first points on the outer peripheral rigid portion. The inner flexible portion has a second portion thereof having a lineal physical dimension substantially equal to the distance between second points on the outer rigid portion where the flexible portion connects to the outer rigid portion. This structure thereby forms a flexible fluid medium ventilation device whenever the flow of the fluid medium is in the direction of the second points from the first points.

United States atent [1 1 Naccarato et al.

[54] VENTILATION DEVICE [76] Inventors: James E. Naccarato, 727 BroadAvenue, Belle Vernon, Pa. 15012; David R. Farkas, 904 Monroe Avenue,McKeesport, Pa. 15133 [22] Filed: Jan.4,1971

[21] Appl.No.: 90,168

[52] U.S.Cl. ..98/2.l2

[51] lnt.Cl. ..B60h 1/24 [58] FieldofSearch ..98/2.12,2.13,88,

[5 6] References Cited UNITED STATES PATENTS 899,257 9/1908 Moody..98/89 972,207 10/1910 Moody....

1,457,959 6/1923 Braucher 1,847,861 3/1932 Bradbury.....

1,978,399 10/1934 Blakeslee....

2,281,840 5/1942 Hamilton 2,640,408 6/1953 Miles 3,434,408 3/1969 Rivers..98/2.13

Primary Examiner-Meyer Perlin Attorney-H. A. Williamson [57] ABSTRACTThis invention relates to a ventilation device which may be used in anaircraft window and which has an outer rigid portion peripherallysurrounding at least a portion of an inner flexible portion andphysically connected thereto. The inner flexible portion has at leastone portion thereof having a lineal physical dimension greater than thedistance between first points on the outer rigid portion where theflexible portion physically connects at the first points on the outerperipheral rigid portion. The inner flexible portion has a secondportion thereof having a lineal physical dimension substantially equalto the distance between second points on the outer rigid portion wherethe flexible portion connects to the outer rigid portion. This structurethereby forms a flexible fluid medium ventilation device whenever theflow of the fluid medium is in the direction of the second points fromthe first points.

11 Claims, 10 Drawing Figures VENTILATION DEVICE This invention relatesto a ventilation device for use in an environment where there is a flowof a fluid medium past the ventilation device, primarily in onedirection.

More specifically, this invention relates to a ventilation device whichhas an outer rigid portion peripherally surrounding at least a portionof an inner flexible portion and physically connected thereto. The innerflexible portion has at least one portion thereof having a linealphysical dimension greater than the distance between first points ontheouter rigid portion where the flexible portion physically connects atthe first points on the outer peripheral rigid portion. The innerflexible portion has a second portion thereof having a lineal physicaldimension substantially equal to the distance between second points onthe outer rigid portion where the flexible portion connects to the outerrigid portion. This structure thereby forms a flexible fluid mediumventilation device whenever the flow of the fluidmedium is in thedirection of the second points from the first points.

In the field of aviation, especially that which is directed towardintermediate priced craft for use in private or small commercialoperations, there has been an ever present need for ventilation of theair crafts cabin especiallywhen taxiing and waiting for clearance totake off. Thetime spent taxiing and waiting for a visual clearance orcontrol tower approval for takeoff provides an especially acute problemin the summer months or even in winter months when the suns rays passthrough the plastic glass of the cockpit and the infrared portion of thesuns rays becomes trapped within the cabin. Some small aircraft usuallyhave only but a single small window which normally opens in a directiontoward the inside of the cockpit or cabin. Little, if any, relief fromthe heat is afforded the occupant or occupants of the cockpit cabin areasince the slip stream of air passing the window of the aircraft createsa lower pressure outside the cockpit, and with few, if any, openings inthe aircraft outside of the slip stream or ground air created bypropeller backwash or taxiing, there is little air circulation present.

To this problem that has existed for years the invention to be describedhereinafter provides a solution to the cabin or cockpit ventilationproblem with such stunning simplicity as to set it in the arena of thoseintellectual creations which merit the dignity afforded by the issuanceof a patent.

A primary object of this inventionis to provide a portable ground airventilation air scoop for use in an aircraft window which includes arigid portion which is positioned at a window of the aircraft and whichair scoop has an inner flexible portion which extends outside of theaircraft window and is drawn into this position by a pressuredifferential between the aircraft cabin and the outside air which movespast the window as a result of aircraft movement and the presence of airnear the ground during taxiing or by the passage of air created bypropeller backwash.

It is therefore a further object of this invention to provide animproved fluid medium ventilation device which utilizes a rigid portionand a flexible portion, the flexible portion providing a fluid mediumscoop device which redirects the fluid medium and thereby provides aventilation device.

Another object of this invention is to provide a portable ventilationdevice having an outer rigid portion and an inner flexible portion whichallows the inner flexible portion to be folded upon itself insubstantially a plane containing the outer rigid portion to therebyprovide a relatively flat, easy to store, and therefore a readilyportable ventilation device.

Still yet another object of this invention is to provide a ventilationdevice having a flexible inner portion which has integral therewith atleast one structural reinforcing region to provide for physicalstability during the passage of the fluid medium into the ventilationdevice while resisting structural flexure from forces directed by thefluid medium coming from directions other than directly into theventilation device.

In the attainment of the foregoing objects the preferred embodiment ofthe invention provides for a portable ground air ventilation scoop incombination with an aircraft window. The air scoop is readilyinstallable in the aircraft window and provides ventilation when thereis a flow of air past the ventilation device primarily in one direction.The air scoop has an outer rigid portion peripherally surrounding atleast a portion of an inner flexible portion and physically connectedthereto. The outer rigid portion has an outer physical dimension greaterthan the opening created by the aircraft window. The inner flexibleportion has at least one portion which has a lineal physical dimensiongreater than the distance between first points on the outer rigidportion where the flexible portion connects the first points on theouter rigid portion.'ln addition, the flexible inner portion has atleast a second portion thereof which has a lineal physical dimensionsubstantially equal to the distance between second points on the outerrigid portion where the flexible portion connects to the outer rigidportion to thereby form a ground air ventilation device whenever theflow of air is in the direction of the second points from the firstpoints.

Other objects and advantages of the invention will become apparent fromthe ensuing description of illustrative embodiments thereof, in thecourse of which reference is had to the accompanying drawings in which:

FIG. 1 illustrates a three-dimensional preferred embodiment of theinvention.

FIG. la is a cross section taken along the lines la la in FIG. 1. 1

FIG. 2 depicts a partial cross section of another embodiment of theinvention which shows a different configuration arrangement.

FIG. 3 sets forth a three-dimensional illustration of another embodimentof the invention.

FIG. 4 shows a preferred embodiment of the invention in its folded or ina readily portable configuration.

FIG. 5 illustrates a three-dimensional view of still yet anotherembodiment of the invention.

FIG. 5a illustrates a portion of another configuration of the inventionalong the lines la la in FIG. 1.

FIG. 6 illustrates the preferred embodiment of the portable ground airscoop ventilation device in use in an aircraft window which opensinwardly.

FIG. 7 illustrates the preferred embodiment of the portable ground airscoop ventilation device in use in an aircraft window which opensoutwardly.

FIG. 8 is an illustration of a highly useful configuration of an airscoop.

Reference is now made to FIG. 1, in which there is depicted a preferredembodiment of the invention where there is illustrated a fluid mediumdepicted by the arrow 17 passing from left to right, as FIG. 1 isviewed. The ventilation device is fabricated of what is basically anouter rigid portion 11 and an inner flexible portion 14. The utility ofthe rigid outer portion 11 and its cooperation with the flexible innerportion 14 will be explained in more detail hereafter. Basically thisfigure depicts a construction in which the outer rigid portion 11 iscomprised of a first rigid element 12 and a second rigid element 13which have sandwiched therebetween a portion of the flexible innerportion 14 designated by reference numeral 16. This lamination, as it isto be referred to, of two outer rigid portions plus a portion of theflexible inner portion 14 is best shown in FIG. la where thecross-section has been taken through the left-hand end of theventilation device depicted in FIG. 1. It should be understood that thematerial utilized for the outer rigid portions 12 and 13 may be of arigid plastic, and the inner flexible portion 14 may also be of aplastic of any suitable type of sufficient strength to withstand thepressures that are incurred by the passage of the fluid medium 17 intothe air ventilation device. When the outer rigid portion is a plasticand the inner flexible portion is also plastic, the entire outer rigidassembly may be heat treated as in the case of thermoplastic materials,and the outer rigid portion, as shown in FIG. 1a. This will form aunitized peripheral structure that totally encompasses the innerflexible portion 14.

Basically, the physical dimensions of the flexible inner portion 14 aresuch that between first points a and 10b, the flexible inner material ofinner portion 14 has a lineal distance measured along its surface thatis greater than the distance between the first points 10a and 10b. Atthe right-hand end of the ventilation device there are second points aand 15b where the lineal dimension of the flexible inner portion 14 isselected to be substantially equal to the distance between the points15a and 15b. When there is a passage of the fluid medium from'left toright, as depicted here, it will become apparent that the flexible innerportion will tend to billow and fill with the fluid medium, and becauseof the dimensions stated with reference to the opening and of theventilation device, between the points 10a and 10b, the fluid medium iscompressed and redirected, as is shown by the dotted arrow 20 seenthrough what is depicted here as a translucent inner flexible portion.In the case here illustrated it may be any gas, or in its latter usageto be described hereafter, the fluid medium is air. The arrow 20represents the passage of the fluid medium from an outer area to aninner area (not shown in detail). The rigid outer portion 11 is designed to fit up against an opening in any physical environment in whichthe flow of the fluid medium is primarily in the direction just notedabove. It may be in a window, or in the alternative, it may be in apipe, other conduit or passageway in which the gas or fluid mediummovement is primarily in one direction. Accordingly, this device, aspresently shown in FIG. 1, remains in its fully inflated condition asshown, as long as there is a flow of the fluid medium into and betweenthe outer rigid portion and the flexible inner portion 14.

FIG. 2 illustrates another method of construction which is contemplatedas being equally suitable for the constructing of a ventilation deviceof the type here under discussion. In this case the outer rigid portions18 and 19 are made of fiber or, as depicted here, wood, and are securedtogether by wood screws 21, 22 and 23 with a portion of the flexibleinner portion 14 sandwiched therebetween, as shown in this illustrationpres-. ented in FIG. 2. The outer rigid portions may be selected fromany material such as plastic, wood, fiber, metal, or glass. 7

Reference is now made to FIG. 3 in which there is depicted a similarventilation device as that shown in FIG. 1 but with additional featuresthat may be necessary when present in certain environmental conditions.In this figure, were applicable, the same reference numerals used inFIG. 1 will also apply. The principal difference in the embodiment ofFIG. 3 is the utilization of reinforcing region elements 28 and 29 ofwhich there are depicted a plurality. These rigid regions may be formedwithin the inner flexible portion 14 by the lamination of small rods inthe direction depicted between two thin portions of flexible innermaterial here shown as a translucent plastic. It will be understood, ofcourse, that when reference is made to flexible inner portions and theuse of plastic as a potential material, it should be recognized that anysuitable flexible material susceptible of flexure may be employed in theventilation scheme here under discussion.

These reinforcing regions 28 and 29, or elements as they may be called,allow for the situation when the fluid medium depicted by arrow 17 isnot the only or predominant pressure or moving mass in which theventilation device is utilized. Therefore, should a direct blast of gasor the fluid medium come from some other direction than that depicted bythe arrow 17, there would tend to be a flexure of the inner portion 14which might tend to collapse or deform the opening of the ventilationdevice at the entry end where the arrow 17 is directed, thereby reducingthe efficiency of the ventilation unit here under discussion.Accordingly, these reinforcing regions may be provided to maintainphysical stability.

There is also depicted in FIG. 3 a number of flange elements 24, 26 and27 whose dimensions and purpose are as follows. The dimensions of theflanges 24 and 27 need only be sufficient to ensure that when theventilation device is pressed into an opening the flanges 24 and 27extend into the openings and provide a means of securing the outer rigidportion to the opening into which the ventilation device is installed.It is apparent that the forces brought about by the entry of the fluidmedium 17 will have a tendency to cause the entire ventilation device toshift its position to the right. To remedy this there may be provided aflange element 26 which also would be dimensioned such that it would fitwithin the opening to which the ventilation device of FIG. 3 wereinserted, thereby providing an inherent barrier to lateral movement inthe direction depicted by the fluid medium arrow 17. This would affordstability to the ventilation device should the pressure created by thepassage of the fluid medium 17 be so great as to cause the entireventilation device to slip within the opening.

FIG. 4 sets forth the preferred embodiment of the ventilation devicedepicted in FIG. 1, with the inner flexible portion folded as shown bythe reference numeral 36 to provide a substantially flat package whichis readily portable and easily stored as its dimension would be littlegreater than the total thickness of the two outer rigid portions 13 and16. This storage capacity and its portability are significant attributesof this improved ventilation scheme.

FIG. 5 represents still yet another embodiment of the invention. Noreference numerals have been used to designate the outer rigid portionsbut in this embodiment it is clearly shown that the outer portion 12aneed only surround a portion of the periphery of the inner flexibleportion 14. In this FIG. 5 the outer rigid portion 12a has a U-shape andprovides a lighter and somewhat less bulky ventilation device. It willbe noted in this embodiment the inner flexible portion 14 is onlyphysically secured to a single outer rigid portion. The physicalconnection of the inner portion to the outer portion may be by means ofan adhesive or other physical attachment technique. In addition to thisaspect it includes a resilient reinforcing region 37 which extendsacross the open end of the U-shaped outer rigid portion 12a. Thisresilient reinforcing region or element 37 may in practice be anyencapsulated metal spring-like element that may have secured thereto amanual actuating tab 38. It can be readily appreciated that pulling thetab 38 in the direction of the arrow 39 would cause the inner flexibleportion, which is held at its opening end in position because of theresilient nature of the portion 37 in an outward open position, to flexwhen pulled by the tab 38 into an inwardly directed position shown bythe dashed line in the direction of the arrow 39. Accordingly, thisprovides and further secures in a different manner two basic functions,one, to hold the ventilation device and its inner flexible portion in afirm but continuously flexed open position; and two, simultaneouslyaffording the user of the ventilation device a tab 38 upon which he maymanually pull the inner flexible portion away from the passage of thefluid medium entering the ventilation device and thereby prevent furtherventilation while he is in the process of removing the ventilationdevice of FIG. 5 from the window or opening into which it has beeninserted.

In FIG. 5a there is shown a slightly different configuration embodyingthe invention where in this case the outer rigid portion 12a may be of atype of plastic which has been made relatively rigid either by making itthicker than the inner flexible portion 14a or by securing it to anothermore rigid plastic portion 12b by any suitable means. In thisconfiguration the air scoop is merely placed in the window and whenfilled with and inflated by incoming air the flexible inner portion 14aballoons, so to speak, and a portion 14b of flexible inner portion 14apresses against the outer surface of window 46, a portion of whichwindow is illustrated here. This pressing aids in securing the air scoopto the plane window 46, thereby holding the entire air scoop inposition.

Turning now to FIG. 6, there is illustrated the preferred embodiment ofthe ventilation device shown utilized in a manner most contemplated.From the figure it is apparent that the aircraft 45 has a side window46, which aircraft window 46 has in turn an inwardly opening window hereshown in dashed outline by reference numeral 48. Inserted in the windowis an air ventilation device which will be referred to in this aircraftembodiment as an air scoop, and which air scoop serves the veryimportant function of providing ventilation to the cabin of the aircraftwhile the aircraft is taxiing in the direction of the arrow 44 or, inthe alternative, when the aircraft is sitting and the only air flowmovement is caused by the propeller 50 which directs a flow of air asshown by the arrows 41, 42 and 43 backward toward the aircraft frontwindow and past the side window 46 of the aircraft. As the air passesthe side of the aircraft window 46 there is experienced a differentialin pressure from within the cabin and that outside the cabin. As the airpasses the window this differential causes the inner flexible portion ofthe air scoop to billow into its open position, as shown in this figure,and allow the passage of the onrushing air 43 into the cockpit where thepilot and passengers are afforded the comfort of circulating air whiletaxiing or waiting for takeoff.

FIG. 7 depicts another environment in which the air ventilation scoop 47is positioned in the aircraft window 46 and which window 46 has anoutwardly opening window 49.

Reference is now made to FIG. 8 in which there is depicted inthree-dimensional form another highly advantageous configuration of anair scoop embodying the invention. As noted earlier the inner flexibleportion 14 is present but the plastic has preset creases 51, 52, 53 and54 that are substantially longitudinal of the inner flexible portion 14.This allows for ready folding as shown by directional arrow 56.

It is therefore seen that this invention provides for a ventilationdevice uniquely adaptable for aircraft usage which by its verysimplicity of construction will afford an advantageous circulation ofair to a hithertofore restricted area of aircraft and will greatlyenhance pilot and passenger comfort during taxiing and before takeoff.

Having thus described our invention, what we claim 1. A portable groundair ventilation scoop in combination with an aircraft window and forready insertion in said aircraft window when there is a flow of air pastsaid ventilation device primarily in one direction, said combinationcomprising,

a. said portable ground air ventilation scoop having an outer rigidportion peripherally surrounding at least a portion of an inner flexibleportion and physically connected thereto, said outer rigid portionhaving an outer physical dimension greater than the opening created bysaid aircraft window,

b. said inner flexible portion having at least one portion thereofhaving a lineal physical dimension greater than the distance betweenfirst points on said outer rigid portion where said flexible portionconnects at said first points on said outer peripheral rigid portion,said flexible inner portion having a degree of flexibility sufficient toallow the flexible portion to fold upon itself in substantially a planecontaining said outer rigid portion to thereby provide a flat, easy tostore, and readily portable venti-' lation device.

2. The portable air ventilation scoop of claim 1, wherein said innerflexible portion has at least a second portion thereof having a linealphysical dimension substantially equal to the distance between secondpoints on the outer rigid portion where said flexible portion connectsto said outer peripheral rigid portion to thereby form a ground airventilation device whenever said flow of air is in the direction of saidsecond points from said first points.

3. The portable air ventilation scoop of claim 2, wherein saidperipheral portion circumferentially surrounds said flexible innerportion.

4. The portable air ventilation scoop of claim 1,

wherein said peripheral portion circumferentially surrounds saidflexible inner portion.

5. The portable air ventilation scoop of claim 1, wherein said outerrigid portion is comprised of two units with at least a portion of saidflexible inner portion interposed therebetween and mutually connected tosaid two units to provide an integral outer rigid portion 6. Theportable air ventilation scoop of claim 1, wherein said flexible innerportion has integral therewith structural reinforcing regions to providefor physical stability during the passage of air from said first pointtoward said second point while resisting structural flexure from forcesdirected by air movement coming from different directions.

7. The portable air ventilation scoop of claim 1, wherein positioned andintegral therewith on said outer rigid peripheral portion is at leastone flange element that protrudes into the window opening therebyenhancing the positioning and retention of said portable air ventilationscoop in said aircraft window.

8. The portable air ventilation scoop of claim 1, wherein said flexibleinner portion has integral therewith a structural reinforcing region ofa resilient nature such that said resilient reinforcing region islocated substantially and integral with said inner flexible portionbetween said first point on said outer peripheral rigid portion.

9. The portable air ventilation scoop of claim 1, wherein said innerflexible portion has an integrally connected tab portion means locatedon an inner surface of said flexible portion to allow the manualwithdrawal of said flexible portion into and through said outerperipheral portion.

10. A ventilation device for use in an environment where there is a flowof a fluid medium past said ventilation device primarily in onedirection, said device comprising,

a. an outer rigid portion peripherally surrounding at least a portion ofan inner flexible portion and physically connected thereto,

b. said inner flexible portion having at least one portion thereofhaving a lineal physical dimension greater than the distance betweenfirst points on said outer rigid portion where said flexible portionconnects at said first points on said outer peripheral rigid portion,said flexible inner portion having a degree of flexibility sufficient toallow the flexible portion to fold upon itself in substantially a planecontaining said outer rigid portion to thereby provide a flat, easy tostore, and readily portable ventilation device,

said inner flexible portion having at least a second portion thereofhaving a lineal physical dimension substantially equal to the distancebetween second points on said outer rigid portion where said flexibleportion connects to said outer peripheral rigid portion to thereby forma flexible fluid medium ventilation device whenever said flow of saidfluid medium is in the direction of said second points from said firstpoints,

said inner flexible portion also having a number of preset creases whichare substantially longitudinal of the inner flexible portion.

11. A ventilation device for use in an environment where there is a flowof a fluid medium past said ventilation device primarily in onedirection, said device comprising,

a. an outer rigid portion peripherally surrounding at least a portion ofan inner flexible portion and physically connected thereto,

b. said inner flexible portion having at least one portion thereofhaving a lineal physical dimension greater than the distance betweenfirst points on said outer rigid portion where said flexible portionconnects at said first points on said outer periph eral rigid portion,said inner flexible portion having a degree of flexibility sufficient toallow the flexible portion to fold upon itself in substantially a planecontaining said outer rigid portion to thereby provide a flat, easy tostore, and readily portable ventilation device,

said inner flexible portion having an integrally connected tab portionmeans located on an inner surface of said flexible portion to allow themanual withdrawal of said flexible portion into and through said outerperipheral portion.

1. A portable ground air ventilation scoop in combination with anaircraft window and for ready insertion in said aircraft window whenthere is a flow of air past said ventilation device primarily in onedirection, said combination comprising, a. said portable ground airventilation scoop having an outer rigid portion peripherally surroundingat least a portion of an inner flexible portion and physically connectedthereto, said outer rigid portion having an outer physical dimensiongreater than the opening created by said aircraft window, b. said innerflexible portion having at least one portion thereof having a linealphysical dimension greater than the distance between first points onsaid outer rigid portion where said flexible portion connects at saidfirst points on said outer peripheral rigid portion, said flexible innerportion having a degree of flexibility sufficient to allow the flexibleportion to fold upon itself in substantially a plane containing saidouter rigid portion to thereby provide a flat, easy to store, andreadily portable ventilation device.
 2. The portable air ventilationscoop of claim 1, wherein said inner flexible portion has at least asecond portion thereof having a lineal physical dimension substantiallyequal to the distance between second points on the outer rigid portionwhere said flexible portion connects to said outer peripheral rigidportion to thereby form a ground air ventilation device whenever saidflow of air is in the direction of said second points from said firstpoints.
 3. The portable air ventilation scoop of claim 2, wherein saidperipheral portion circumferentially surrounds said flexible innerportion.
 4. The portable air ventilation scoop of claim 1, wherein saidperipheral portion circumferentially surrounds said flexible innerportion.
 5. The portable air ventilation scoop of claim 1, wherein saidouter rigid portion is comprised of two units with at least a portion ofsaid flexible inner portion interposed therebetween and mutuallyconnected to said two units to provide an integral outer rigid portion6. The portable air ventilation scoop of claim 1, wherein said flexibleinner portion has integral therewith structural reinforcing regions toprovide for physical stability during the passage of air from said firstpoint toward said second point while resisting structural flexure fromforces directed by air movement coming from different directions.
 7. Theportable air ventilation scoop of claim 1, wherein positioned andintegral therewith on said outer rigid peripheral portion is at leastone flange element that protrudes into the window opening therebyenhancing the positioning and retention of said portable air ventilationscoop in said aircraft window.
 8. The portable air ventilation scoop ofclaim 1, wherein said flexible inner portion has integral therewith astructural reinforcing region of a resilient nature such that saidresilient reinforcing region is located substantially and integral withsaid inner flexible portion between said first point oN said outerperipheral rigid portion.
 9. The portable air ventilation scoop of claim1, wherein said inner flexible portion has an integrally connected tabportion means located on an inner surface of said flexible portion toallow the manual withdrawal of said flexible portion into and throughsaid outer peripheral portion.
 10. A ventilation device for use in anenvironment where there is a flow of a fluid medium past saidventilation device primarily in one direction, said device comprising,a. an outer rigid portion peripherally surrounding at least a portion ofan inner flexible portion and physically connected thereto, b. saidinner flexible portion having at least one portion thereof having alineal physical dimension greater than the distance between first pointson said outer rigid portion where said flexible portion connects at saidfirst points on said outer peripheral rigid portion, said flexible innerportion having a degree of flexibility sufficient to allow the flexibleportion to fold upon itself in substantially a plane containing saidouter rigid portion to thereby provide a flat, easy to store, andreadily portable ventilation device, said inner flexible portion havingat least a second portion thereof having a lineal physical dimensionsubstantially equal to the distance between second points on said outerrigid portion where said flexible portion connects to said outerperipheral rigid portion to thereby form a flexible fluid mediumventilation device whenever said flow of said fluid medium is in thedirection of said second points from said first points, said innerflexible portion also having a number of preset creases which aresubstantially longitudinal of the inner flexible portion.
 11. Aventilation device for use in an environment where there is a flow of afluid medium past said ventilation device primarily in one direction,said device comprising, a. an outer rigid portion peripherallysurrounding at least a portion of an inner flexible portion andphysically connected thereto, b. said inner flexible portion having atleast one portion thereof having a lineal physical dimension greaterthan the distance between first points on said outer rigid portion wheresaid flexible portion connects at said first points on said outerperipheral rigid portion, said inner flexible portion having a degree offlexibility sufficient to allow the flexible portion to fold upon itselfin substantially a plane containing said outer rigid portion to therebyprovide a flat, easy to store, and readily portable ventilation device,said inner flexible portion having an integrally connected tab portionmeans located on an inner surface of said flexible portion to allow themanual withdrawal of said flexible portion into and through said outerperipheral portion.